DNA PROFILING
THE NEW
SCIENCE
OF IDENTITY
By CASSANDRA FRANKLIN-BARBAJOSA
NATIONAL GEOGRAPHIC EDITORIAL STAFF
Photographs by PETER MENZEL
Mission accomplished: A
scientific search finds
convincing evidence of
ways in which individ
uals differ at the most
basic level. It has produced a
technology that answers identity
questions in areas ranging from
paternity to murder.
Through a series of manip
ulations at the molecular level,
researchers can now make
images of specific sequences of
DNA (deoxyribonucleic acid).
These genetic profiles, in some
cases called fingerprints, can be
as singular as a signature and
establish identity with far more
reliability than the conventional
blood-typing used to implicate a
crime suspect.
But criminal investigation is
just one use for this new tech
nology. Zoologists fingerprint
endangered species living in the
wild to learn breeding patterns.
For animals in captivity, finger
prints can identify unrelated
pairs that can be bred to
increase genetic diversity.
At the Howard Hughes Medi
cal Institute in Salt Lake City,
Utah, geneticists isolate a small
fragment of DNA (right) mark
ing the gene that causes neuro
fibromatosis type 1-an often
painful condition afflicting one
in 3,500 people worldwide with
brown spots and benign tumors.
Restoring health to leukemia
patients is the primary concern
of doctors who use DNA finger
printing to gauge the success of
bone-marrow transplants.
The ability to identify inher
ited traits transferred through
DNA helps reunite immigrant
families separated by oceans,
both real and bureaucratic.
Researchers also extract
DNA from mummified human
remains. By comparing ancient
peoples and related contempo
rary cultures, scientists can
reach back millennia to better
reconstruct human history.
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